The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Radio-frequency identification (RFID) generally refers to the automatic identification method using radio waves that relies on storing and remotely retrieving data from devices called RFID tags or transponders. RFID readers are the devices used to read the information or data in the RFID tag. The RFID tag may be attached to or incorporated into various things, such as commercial products, etc.
RFID tags may be chip-based and contain antennas and integrated circuits. The particular antenna used for a RFID tag is usually affected by the intended application and the frequency of operation. To this end, some RFID tags include patch-antennas. RFID tag antennas are relatively low power antennas configured to obtain enough microwave power from a more powerful RFID reader antenna to “charge” an integrated circuit of the RFID tag. The integrated circuit keeps or stores information about the tagged item, such as price of the consumer good being purchased, etc. RFID tag antennas are designed to work with their specific integrated circuits by matching the RFID tag antennas to the high impedance of their integrated circuits.
In comparison, RFID reader antennas are more complicated antennas than RFID tag antennas. For example, RFID reader antennas have much higher power requirements and are circularly polarized. Conversely, RFID tag antennas are fairly inexpensive antennas (e.g., antennas printed on plastic sheets). RFID tag antennas also may have much simpler polarization requirements (e.g., linear polarization) compared to the polarization requirements for RFID reader antennas (e.g., circular polarization).